1. Field of the Invention
Aspect of the invention relate to quality measurement of an input signal, and more particularly, to a signal quality measuring apparatus and method thereof, whereby a quality of an input signal is measured based on level information of the input signal, wherein the level information is extracted according to a relationship between the input signal and a binary signal generated from the input signal.
2. Description of the Related Art
A binary signal is recorded in a storage medium such as an optical disc. However, a radio frequency (RF) signal read from the optical disc has an analog signal characteristic due to a characteristic of the optical disc and an optical characteristic, and a magnitude of the RF signal decreases as recording density increases, such that distortion of a reproduction signal increases with the addition of only a small amount of noise.
Thus, in an optical device field using a high density optical disc, in order to improve a quality of the reproduction signal, techniques have been proposed to measure a quality of an input signal based on a relationship between the input signal (or, an RF signal) in an analog form and a binary signal of the input signal.
In particular, techniques have been proposed to extract level information of the input signal by referring to the relationship between the input signal and the binary signal of the input signal, and to measure the quality of the input signal based on the extracted level information of the input signal. However, an amplitude of a short periodic signal is different from an amplitude of a long periodic signal according to a channel characteristic, and a technique capable of measuring the quality of the input signal according to the channel characteristic is not found in the related art.